@article{HeddergottKruegerBabuetal.2012,
author = {Heddergott, Nico and Kr{\"u}ger, Timothy and Babu, Sujin B. and Wei, Ai and Stellamanns, Erik and Uppaluri, Sravanti and Pfohl, Thomas and Stark, Holger and Engstler, Markus},
title = {Trypanosome Motion Represents an Adaptation to the Crowded Environment ofthe Vertebrate Bloodstream},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-78421},
year = {2012},
abstract = {Blood is a remarkable habitat: it is highly viscous, contains a dense packaging of cells and perpetually flows at velocities varying over three orders of magnitude. Only few pathogens endure the harsh physical conditions within the vertebrate bloodstream and prosper despite being constantly attacked by host antibodies. African trypanosomes are strictly extracellular blood parasites, which evade the immune response through a system of antigenic variation and incessant motility. How the flagellates actually swim in blood remains to be elucidated. Here, we show that the mode and dynamics of trypanosome locomotion are a trait of life within a crowded environment. Using high-speed fluorescence microscopy and ordered micro-pillar arrays we show that the parasites mode of motility is adapted to the density of cells in blood. Trypanosomes are pulled forward by the planar beat of the single flagellum. Hydrodynamic flow across the asymmetrically shaped cell body translates into its rotational movement. Importantly, the presence of particles with the shape, size and spacing of blood cells is required and sufficient for trypanosomes to reach maximum forward velocity. If the density of obstacles, however, is further increased to resemble collagen networks or tissue spaces, the parasites reverse their flagellar beat and consequently swim backwards, in this way avoiding getting trapped. In the absence of obstacles, this flagellar beat reversal occurs randomly resulting in irregular waveforms and apparent cell tumbling. Thus, the swimming behavior of trypanosomes is a surprising example of micro-adaptation to life at low Reynolds numbers. For a precise physical interpretation, we compare our high-resolution microscopic data to results from a simulation technique that combines the method of multi-particle collision dynamics with a triangulated surface model. The simulation produces a rotating cell body and a helical swimming path, providing a functioning simulation method for a microorganism with a complex swimming strategy},
subject = {Biologie},
language = {en}
}
@article{HaertleinSchiesslWagneretal.1983,
author = {H{\"a}rtlein, Michael and Schiessl, Sigrid and Wagner, Wilma and Rdest, Ursula and Kreft, J{\"u}rgen and Goebel, Werner},
title = {Transport of hemolysin by Escherichia coli},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-60619},
year = {1983},
abstract = {No abstract available},
subject = {Biologie},
language = {en}
}
@article{LampidisGrossSokolovicetal.1994,
author = {Lampidis, Robert and Gross, Roy and Sokolovic, Zeljka and Goebel, Werner and Kreft, J{\"u}rgen},
title = {The virulence regulator protein of Listeria ivanovii is highly homologous to PrfA from Listeria monocytogenes and both belong to the Crp-Fnr family of transcription regulators},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-60503},
year = {1994},
abstract = {No abstract available},
subject = {Biologie},
language = {en}
}
@article{HoppeSebald1984,
author = {Hoppe, J. and Sebald, Walter},
title = {The proton conducting F0-part of bacterial ATP synthases},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-82019},
year = {1984},
abstract = {No abstract available},
subject = {Biologie},
language = {en}
}
@article{KoetschanFoersterKelleretal.2010,
author = {Koetschan, Christian and Foerster, Frank and Keller, Alexander and Schleicher, Tina and Ruderisch, Benjamin and Schwarz, Roland and Mueller, Tobias and Wolf, Matthias and Schultz, Joerg},
title = {The ITS2 Database III-sequences and structures for phylogeny},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-68390},
year = {2010},
abstract = {The internal transcribed spacer 2 (ITS2) is a widely used phylogenetic marker. In the past, it has mainly been used for species level classifications. Nowadays, a wider applicability becomes apparent. Here, the conserved structure of the RNA molecule plays a vital role. We have developed the ITS2 Database (http://its2.bioapps .biozentrum.uni-wuerzburg.de) which holds information about sequence, structure and taxonomic classification of all ITS2 in GenBank. In the new version, we use Hidden Markov models (HMMs) for the identification and delineation of the ITS2 resulting in a major redesign of the annotation pipeline. This allowed the identification of more than 160 000 correct full ength and more than 50 000 partial structures. In the web interface, these can now be searched with a modified BLAST considering both sequence and structure, enabling rapid taxon sampling. Novel sequences can be annotated using the HMM based approach and modelled according to multiple template structures. Sequences can be searched for known and newly identified motifs. Together, the database and the web server build an exhaustive resource for ITS2 based phylogenetic analyses.},
subject = {Biologie},
language = {en}
}
@inproceedings{FialaFederleMaschwitzetal.1994,
author = {Fiala, Brigitte and Federle, W. and Maschwitz, U. and Azarae, Idris},
title = {The first myrmecophytic 2-partner-system in the genus Macaranga: The association between Macaranga puncticulata and a Componotus (Colobopsis) in Malaysia},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-55144},
year = {1994},
abstract = {No abstract available},
subject = {Biologie},
language = {en}
}
@article{HeisigWeberEnglbergeretal.2012,
author = {Heisig, Julia and Weber, David and Englberger, Eva and Winkler, Anja and Kneitz, Susanne and Sung, Wing-Kin and Wolf, Elmar and Eilers, Martin and Wei, Chia-Lin and Gessler, Manfred},
title = {Target Gene Analysis by Microarrays and Chromatin Immunoprecipitation Identifies HEY Proteins as Highly Redundant bHLH Repressors},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-75341},
year = {2012},
abstract = {HEY bHLH transcription factors have been shown to regulate multiple key steps in cardiovascular development. They can be induced by activated NOTCH receptors, but other upstream stimuli mediated by TGFß and BMP receptors may elicit a similar response. While the basic and helix-loop-helix domains exhibit strong similarity, large parts of the proteins are still unique and may serve divergent functions. The striking overlap of cardiac defects in HEY2 and combined HEY1/HEYL knockout mice suggested that all three HEY genes fulfill overlapping function in target cells. We therefore sought to identify target genes for HEY proteins by microarray expression and ChIPseq analyses in HEK293 cells, cardiomyocytes, and murine hearts. HEY proteins were found to modulate expression of their target gene to a rather limited extent, but with striking functional interchangeability between HEY factors. Chromatin immunoprecipitation revealed a much greater number of potential binding sites that again largely overlap between HEY factors. Binding sites are clustered in the proximal promoter region especially of transcriptional regulators or developmental control genes. Multiple lines of evidence suggest that HEY proteins primarily act as direct transcriptional repressors, while gene activation seems to be due to secondary or indirect effects. Mutagenesis of putative DNA binding residues supports the notion of direct DNA binding. While class B E-box sequences (CACGYG) clearly represent preferred target sequences, there must be additional and more loosely defined modes of DNA binding since many of the target promoters that are efficiently bound by HEY proteins do not contain an Ebox motif. These data clearly establish the three HEY bHLH factors as highly redundant transcriptional repressors in vitro and in vivo, which explains the combinatorial action observed in different tissues with overlapping expression.},
subject = {Biologie},
language = {en}
}
@article{HsiehLinsenmair2012,
author = {Hsieh, Yu-Lung and Linsenmair, Karl Eduard},
title = {Seasonal dynamics of arboreal spider diversity in a temperate forest},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-75158},
year = {2012},
abstract = {Measuring and estimating biodiversity patterns is a fundamental task of the scientist working to support conservation and informmanagement decisions.Most biodiversity studies in temperate regions were often carried out over a very short period of time (e.g., a single season) and it is often—at least tacitly—assumed that these short-termfindings are representative of long-termgeneral patterns.However, should the studied biodiversity pattern in fact contain significant temporal dynamics, perhaps leading to contradictory conclusions. Here, we studied the seasonal diversity dynamics of arboreal spider communities dwelling in 216 European beeches (Fagus sylvatica L.) to assess the spider community composition in the following seasons: two cold seasons (I:November 2005-January 2006; II: February-April) and two warm seasons (III: May-July; IV: August-October). We show that the usually measured diversity of the warmseason community (IV: 58 estimated species) alone did not deliver a reliable image of the overall diversity present in these trees, and therefore, we recommend it should not be used for sampling protocols aimed at providing a full picture of a forest's biodiversity in the temperate zones. In particular, when the additional samplings of other seasons (I, II, III) were included, the estimated species richness nearly doubled (108). Community I possessed the lowest diversity and evenness due to the harsh winter conditions: this community was comprised of one dominant species together with several species low in abundance. Similarity was lowest (38.6\%) between seasonal communities I and III, indicating a significant species turnover due to recolonization, so that community III had the highest diversity. Finally, using nonparametric estimators, we found that further sampling in late winter (February-April) is most needed to complete our inventory. Our study clearly demonstrates that seasonal dynamics of communities should be taken into account when studying biodiversity patterns of spiders, and probably forest arthropods in general.},
subject = {Biologie},
language = {en}
}
@article{KreftFunkeHaasetal.1989,
author = {Kreft, J{\"u}rgen and Funke, Dorothee and Haas, Albert and Lottspeich, Friedrich and Goebel, Werner},
title = {Production, purification and characterization of hemolysins from Listeria ivanovii and Listeria monocytogenes Sv4b.},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-60545},
year = {1989},
abstract = {In culture supematants of both Listeria ivanovii and Listeria monocytogenes Sv4b, for the first time a hemolysin of molecular weight 58 kDa was identified, which had all the characteristics of an SH-activated cytolysin, and which was therefore identified as Iisteriolysin 0 (LLO). In the case of L. ivanovii a second major supematant protein of molecular weight 24 kDa co-purified with LLO. However, the function of this protein has to be determined. In culture supematants of L. ivanovii a sphingomyelinase and a Iecithinase activity could be detected, both enzymatic activities together contributing to the pronounced hemolysis caused by L. ivanovii. The N-tenninal amino acid sequences of LLO and the 24 kDa from L. ivanovii are shown.},
subject = {Biologie},
language = {en}
}
@article{SchueleinKreftGonskietal.1991,
author = {Sch{\"u}lein, Ralf and Kreft, J{\"u}rgen and Gonski, Sigrid and Goebel, Werner},
title = {Preprosubtilisin Carlsberg processing and secretion is blocked after deletion of amino acids 97-101 in the mature part of the enzyme},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-60577},
year = {1991},
abstract = {During an investigation into the substrate specificity and processing of subtilisin Carlsberg from Bacillus licheniformis, two major independent findings were made: (i) as has been shown previously, a stretch of five amino acids (residues 97-101 of the mature enzyme) that loops out into the binding cleft is involved in substrate binding by subtilisin Carlsberg. In order to see whether this loop element also determines substrate specificity, the coding region for these five amino acids was deleted from the cloned gene for subtilisin Carlsberg by site-directed mutagenesis. Unexpectedly the resulting mutant preproenzyme (P42c, Mr=42 kDa) was not processed to the mature form (Mr = 30 kDa) and was not released into the medium by a proteasedeficient B. subtilis host strain; rather, it accumulated in the cell membrane. This result demonstrates that the integrity of this loop element, which is very distant from the processing cleavage sites in the preproenzyme, is required for secretion of subtilisin Carlsberg. (ii) In culture supernatants from B. subtilis harbouring the cloned wild-type subtilisin Carlsberg gene the transient appearance (at 0-3 h after onset of stationary phase) of a processing intermediate (P38c, Mr = 38 kDa) oftbis protease could be demonstrated. P38c very probably represents a genuine proform of subtilisin Carlsberg.},
subject = {Biologie},
language = {en}
}